What Are Dna Monomers Called

Deoxyribonucleic acid Structure Action

Problem 10: Review of the Features of the Watson-Crick Model for DNA Structure

Components of DNA

DNA is a polymer. The monomer units of DNA are nucleotides, and the polymer is known as a "polynucleotide." Each nucleotide consists of a 5-carbon saccharide (deoxyribose), a nitrogen containing base of operations attached to the saccharide, and a phosphate grouping. In that location are 4 unlike types of nucleotides found in Dna, differing only in the nitrogenous base. The four nucleotides are given i letter abbreviations as autograph for the iv bases.

A is for adenine
G is for guanine
C is for cytosine
T is for thymine

DNA Bases

Adenine and guanine are purines. Purines are the larger of the ii types of bases institute in Dna. The nine atoms that make up the fused rings (5 carbon, 4 nitrogen) are numbered 1-ix. All ring atoms prevarication in the same aeroplane. Cytosine and thymine are pyrimidines. The vi atoms (4 carbon, 2 nitrogen) are numbered 1-half-dozen. Like purines, all pyrimidine band atoms lie in the same plane.

Deoxyribose Sugar

The deoxyribose sugar of the DNA backbone has 5 carbons and iii oxygens. The carbon atoms are numbered 1', 2', 3', 4', and v' to distinguish from the numbering of the atoms of the purine and pyrmidine rings. The hydroxyl groups on the 5'- and 3'- carbons link to the phosphate groups to form the Deoxyribonucleic acid backbone. Deoxyribose lacks an hydroxyl grouping at the ii'-position when compared to ribose, the sugar component of RNA.

Nucleosides and Nucleotides

A nucleoside is 1 of the iv DNA bases covalently attached to the C1' position of a sugar. The sugar in deoxynucleosides is two'-deoxyribose. The sugar in ribonucleosides is ribose. Nucleosides differ from nucleotides in that they lack phosphate groups. The four different nucleosides of Deoxyribonucleic acid are deoxyadenosine (dA), deoxyguanosine (dG), deoxycytosine (dC), and (deoxy)thymidine (dT, or T). In dA and dG, there is an "N-glycoside" bond betwixt the saccharide C1' and N9 of the purine. A nucleotide is a nucleoside with one or more phosphate groups covalently attached to the 3'- and/or 5'-hydroxyl group(s).

DNA Backbone

The DNA courage is a polymer with an alternate carbohydrate-phosphate sequence. The deoxyribose sugars are joined at both the three'-hydroxyl and 5'-hydroxyl groups to phosphate groups in ester links, also known as "phosphodiester" bonds.

DNA Double Helix

DNA is a usually double stranded macromolecule. Two polynucleotide chains, held together by weak thermodynamic forces, form a Deoxyribonucleic acid molecule.

Features of the DNA Double Helix

2 DNA strands form a helical spiral, winding around a helix axis in a correct-handed spiral.
The ii polynucleotide chains run in opposite directions.
The saccharide-phosphate backbones of the two Deoxyribonucleic acid strands wind around the helix axis like the railing of a sprial staircase.
The bases of the individual nucleotides are on the within of the helix, stacked on top of each other like the steps of a spiral staircase.

Base Pairs

Inside the Deoxyribonucleic acid double helix, A forms 2 hydrogen bonds with T on the opposite strand, and G forms 3 hyrdorgen bonds with C on the opposite strand. dA-dT and dG-dC base pairs are the same length, and occupy the same space within a Dna double helix. Therefore the Deoxyribonucleic acid molecule has a uniform diameter. dA-dT and dG-dC base pairs can occur in any order within DNA molecules

Dna Helix Axis

The helix centrality is nearly apparent from a view directly downward the axis. The sugar-phosphate backbone is on the exterior of the helix where the polar phosphate groups (red and yellow atoms) can interact with the polar environment. The nitrogen (blue atoms) containing bases are inside, stacking perpendicular to the helix axis.